IREB2 and Hyperglycemia: Irp2−/− mice showed fasting hyperglycemia (WT, 6.06 ± 0.23 versus Irp2−/−, 7.17 ± 0.39 mmol glucose/L; p = 0.02; Fig. 2c) and reduced basal plasma insulin concentrations (WT, 1.87 ± 0.773 versus 0.489 ± 0.105 ng/ml insulin, p < 0.05; Fig. 2d).